The present invention relates to a fastener setting tool of type that breaks the mandrel of the fastener such as blind rivet and lock-bolt upon fastening operation, and more specifically relates to a blind rivet setting tool having a broken piece collecting assembly for collecting the broken pieces of the mandrels from a nose through a path within the tool.
It is well known that a blind rivet comprises of a hollow rivet body and a mandrel inserted into the rivet body. Generally, a hydraulic actuated blind rivet setting tool is used to fasten the blind rivets to a workpiece. The blind rivet setting tool is provided with a chuck mechanism for holding the mandrel of the blind rivet, at the nose end of an elongated housing. The mandrel of a blind rivet is inserted into the nose, and the rivet body projected from the nose is inserted into the mounting hole of the workpiece such as a panel. When the rivet setting tool is triggered under that condition, a chuck mechanism is driven in a retracting direction in the housing by its hydraulic piston, so that the mandrel is pulled enough to break the mandrel at a predetermined breaking point to enlarge the shank portion of the rivet body to fix the rivet body to the workpiece by the enlarged shank portion and a flange of the rivet body. Furthermore, the broken pieces of the mandrel are released from the chuck mechanism, transported in an axial direction within the housing, and collected in a broken piece collecting container mounted at other end of the housing. In order to transfer the broken pieces to the broken piece collecting container, a path formed in the housing through which the broken piece passes or a mechanism for applying a suction negative pressure on the collecting container may also be provided. One example of such fastener setting tools is described in Japanese Patent Laid-Open No. 07-299539. Also, in Japanese U. M. Publication No. 07-023087, a similar blind rivet setting tool having a collecting container for containing the broken pieces of the mandrels at the rear end of the elongated housing of the tool is disclosed.
FIGS. 1 and 2 show one example of prior blind rivet setting tools similar to that of above Japanese Patent Laid Open No. 07-299539. In FIGS. 1 and 2, a blind rivet setting tool 1 includes a handle 2, a hydraulic pressure generating means 3, and a housing 5. A nose 6 at the front end of the housing 5 is provided with a chuck mechanism (not shown) for holding the mandrel of the blind rivet. Furthermore, in the rear portion of the housing 5, a path 9 is formed through which the broken piece of the mandrel passes from the nose of the front end to the rear end of the housing. The broken piece of the mandrel is transported into a collecting container 7, for example, by a suction negative mechanism or the like as shown in FIGS. 4(a) and (b) of Japanese Patent Laid Open No. 07-299539. When a certain amount of the broken pieces have been collected in the collecting container 7, the collecting container 7 is rotated to align a opening 10 of the outer container portion with a opening of the inner container portion as shown in FIG. 2, and then the broken pieces of the mandrels are discharged from that aligned openings for disposal .
There are various types of the blind rivet. Thus, the lengths of the broken pieces of the mandrels are different according to their types. If the length of the broken piece is near the inner diameter of the collecting container, the broken pieces might be engaged with the inner wall of the container, so the broken pieces of the mandrels could not disposed. This situation is shown in FIGS. 3(a) and (b). If the broken pieces 11 of the mandrels are entangled to each other as shown in FIG. 3(b), they block the outlet port of the path 9 to be accumulated within the path 9 of the housing, and finally they interfere with the operation of the blind rivet setting tool. Furthermore, in the case that the collecting container structure shown in FIG. 2, there is a fear that the opening 10 could not be opened. Therefore, it is desirable to eliminate the entangling of the broken pieces within the collecting container. Japanese U. M. Laid Open No. 62-105735 discloses a safety cover assembly which prevents a risk of emitting the broken pieces, by mounting a cylindrical safety cover having a small diameter on the outlet port of the path for the broken pieces. Since this safety cover is for receiving the broken pieces one by one to discharge them outside, rather than for providing a collecting container for the broken pieces, it does not resolve the above problem of entangling of the broken pieces as discussed above.